The Make-a-Wish Foundation contacted actor Ron Perlman on behalf of Zachary, a young boy who wanted two things: to meet and become Hellboy. Perlman reprised his titular role in the Hellboy movies by going through the long makeup application process and appearing in character. Later, the same makeup artists turned Zachary into a little demon with facepaint and prosthetic appliances. You can view more pictures of their day together at the link.